Ventilation fan



FIG. 1 is a perspective view of a ventilation fan showing our new design;

FIG. 2 is a front elevational view thereof;

FIG. 3 is a rear elevational view thereof;

FIG. 4 is a left side elevational view thereof;

FIG. 5 is a right side elevational view thereof;

FIG. 6 is a top plan view thereof;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is an enlarged view of the area A indicated in FIG. 1; and,

FIG. 9 is an exploded view of FIG. 1.

The broken lines illustrate portion of the ventilation fan and form no part of the claimed design. The broken line rectangle surrounding the area A in FIG. 1 and FIG. 8 form no part of the claimed design. 

CLAIM The ornamental design for a ventilation fan, as shown and described. 